Spatial light modulators (SLMS) are devices that modulate incident light in a spatial pattern to form an image corresponding to an electrical or optical input received by the SLM. The incident light may be modulated in phase, intensity, polarization, or direction. SLMs have numerous applications. For example, SLMs are currently used in the areas of projection displays, video and graphics monitors, televisions, optical information processing and electrophotographic printing.
An SLM is typically comprised of an array of individually addressable picture elements that correspond to the pixels in a frame of image data. A stream of image data is input to the SLM and each individual picture element is driven according to a corresponding pixel in a frame of the image data. The image data is thus displayed on the SLM one frame at a time
One type of SLM is a micro-mirror array in which each of the individually addressable picture elements is a microscopic mirror that can be moved according to the image data received. Conventional micro-mirror devices include an array of electrostatically actuated mirrors fabricated by CMOS (complementary metal-oxide-semiconductor) compatible processes over a memory cell on a silicon substrate. To meet the high frequency requirements for some video applications, the device must be able to drive each micro-mirror from one extreme landed position to another with a relatively high speed. This must be done while transition time and impact energy are minimized and operational robustness is maximized.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.